More than 15 years after the publication of the agile manifesto of software development, agile development approaches have also reached the processes of physical product development. Because of the boundary conditions and requirements here, which differ strongly from those of pure software development, these approaches often reach their limits. However, research and practice have quickly recognized that hybrid approaches integrate the strengths of agile and plan-driven development. This paper presents 25 hybrid development approaches that have been identified in a Systematic Literature Review.